Ab initio theory for current-induced molecular switching: Melamine on Cu(001)
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AbstractMelamine on Cu(001) is mechanically unstable under the current of a scanning tunneling microscope tip and can switch among configurations. However, these are not equally accessible, and the switching critical current depends on the bias polarity. In order to explain such rich phenomenology, we have developed a scheme to evaluate the evolution of the reaction paths and activation barriers as a function of bias, which is rooted in the nonequilibrium Green's function method implemented within density functional theory. This, combined with the calculation of the inelastic electron tunneling spectroscopy signal, allows us to identify the vibrational modes promoting the observed molecular conformational changes. Finally, once our ab initio results are used within a resonance model, we are able to explain the details of the switching behavior, such as its dependence on the bias polarity, and the noninteger power relation between the reaction rate constants and both the bias voltage and the electric current. © 2013 American Physical Society.
CitationOhto T, Rungger I, Yamashita K, Nakamura H, Sanvito S (2013) Ab initio theory for current-induced molecular switching: Melamine on Cu(001) . Physical Review B 87. Available: http://dx.doi.org/10.1103/PhysRevB.87.205439.
SponsorsThis research was supported by a Global Centers of Excellence Program from the Ministry of Education, Culture, Sports, Science and Technology of Japan and the Japan Society for the Promotion of Science. I.R. and S.S. thank King Abdullah University of Science and Technology for financial support (Acrab project). H.N. received financial support from the Scientific Research on Innovative Areas, MEXT grant-in-aid project “Materials Design through Computics” (Project No. 23104514). Computational resources have been provided by the Trinity Centre for High Performance Computing, Ireland.
PublisherAmerican Physical Society (APS)
JournalPhysical Review B